 /*******************************************************************************
  * Copyright (c) 2000, 2006 IBM Corporation and others.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
  * http://www.eclipse.org/legal/epl-v10.html
  *
  * Contributors:
  * IBM Corporation - initial API and implementation
  *******************************************************************************/
 package org.eclipse.core.internal.resources;

 import java.io.IOException ;
 import java.io.InputStream ;
 import java.util.ArrayList ;
 import java.util.List ;
 import javax.xml.parsers.*;
 import org.eclipse.core.internal.localstore.SafeFileInputStream;
 import org.eclipse.core.internal.utils.Messages;
 import org.eclipse.core.internal.utils.Policy;
 import org.eclipse.core.resources.IResourceStatus;
 import org.eclipse.core.runtime.IPath;
 import org.eclipse.osgi.util.NLS;
 import org.w3c.dom.*;
 import org.xml.sax.SAXException ;

 /**
  * This class contains legacy code only. It is being used to read workspace
  * descriptions which are obsolete.
  */
 public class WorkspaceDescriptionReader implements IModelObjectConstants {
     /** constants */
     protected static final String [] EMPTY_STRING_ARRAY = new String [0];

     public WorkspaceDescriptionReader() {
         super();
     }

     protected String getString(Node target, String tagName) {
         Node node = searchNode(target, tagName);
         return node != null ? (node.getFirstChild() == null ? null : node.getFirstChild().getNodeValue()) : null;
     }

     protected String [] getStrings(Node target) {
         if (target == null)
             return null;
         NodeList list = target.getChildNodes();
         if (list.getLength() == 0)
             return EMPTY_STRING_ARRAY;
         List result = new ArrayList (list.getLength());
         for (int i = 0; i < list.getLength(); i++) {
             Node node = list.item(i);
             if (node.getNodeType() == Node.ELEMENT_NODE)
                 result.add(read(node.getChildNodes().item(0)));
         }
         return (String []) result.toArray(new String [result.size()]);
     }

     /**
      * A value was discovered in the workspace description file that was not a number.
      * Log the exception.
      */
     private void logNumberFormatException(String value, NumberFormatException e) {
         String msg = NLS.bind(Messages.resources_readWorkspaceMetaValue, value);
         Policy.log(new ResourceStatus(IResourceStatus.FAILED_READ_METADATA, null, msg, e));
     }

     public Object read(InputStream input) {
         try {
             DocumentBuilder parser = DocumentBuilderFactory.newInstance().newDocumentBuilder();
             Document document = parser.parse(input);
             return read(document.getFirstChild());
         } catch (IOException e) {
             // ignore
 } catch (SAXException e) {
             // ignore
 } catch (ParserConfigurationException e) {
             // ignore
 }
         return null;
     }

     public Object read(IPath location, IPath tempLocation) throws IOException {
         SafeFileInputStream file = new SafeFileInputStream(location.toOSString(), tempLocation.toOSString());
         try {
             return read(file);
         } finally {
             file.close();
         }
     }

     protected Object read(Node node) {
         if (node == null)
             return null;
         switch (node.getNodeType()) {
             case Node.ELEMENT_NODE :
                 if (node.getNodeName().equals(WORKSPACE_DESCRIPTION))
                     return readWorkspaceDescription(node);
             case Node.TEXT_NODE :
                 String value = node.getNodeValue();
                 return value == null ? null : value.trim();
             default :
                 return node.toString();
         }
     }

     /**
      * read (String, String) hashtables
      */
     protected WorkspaceDescription readWorkspaceDescription(Node node) {
         // get values
 String name = getString(node, NAME);
         String autobuild = getString(node, AUTOBUILD);
         String snapshotInterval = getString(node, SNAPSHOT_INTERVAL);
         String fileStateLongevity = getString(node, FILE_STATE_LONGEVITY);
         String maxFileStateSize = getString(node, MAX_FILE_STATE_SIZE);
         String maxFileStates = getString(node, MAX_FILE_STATES);
         String [] buildOrder = getStrings(searchNode(node, BUILD_ORDER));

         // build instance
 //invalid values are skipped and defaults are used instead
 WorkspaceDescription description = new WorkspaceDescription(name);
         if (autobuild != null)
             //if in doubt (value is corrupt) we want autobuild on
 description.setAutoBuilding(!autobuild.equals(Integer.toString(0)));
         try {
             if (fileStateLongevity != null)
                 description.setFileStateLongevity(Long.parseLong(fileStateLongevity));
         } catch (NumberFormatException e) {
             logNumberFormatException(fileStateLongevity, e);
         }
         try {
             if (maxFileStateSize != null)
                 description.setMaxFileStateSize(Long.parseLong(maxFileStateSize));
         } catch (NumberFormatException e) {
             logNumberFormatException(maxFileStateSize, e);
         }
         try {
             if (maxFileStates != null)
                 description.setMaxFileStates(Integer.parseInt(maxFileStates));
         } catch (NumberFormatException e) {
             logNumberFormatException(maxFileStates, e);
         }
         if (buildOrder != null)
             description.internalSetBuildOrder(buildOrder);
         try {
             if (snapshotInterval != null)
                 description.setSnapshotInterval(Long.parseLong(snapshotInterval));
         } catch (NumberFormatException e) {
             logNumberFormatException(snapshotInterval, e);
         }
         return description;
     }

     protected Node searchNode(Node target, String tagName) {
         NodeList list = target.getChildNodes();
         for (int i = 0; i < list.getLength(); i++) {
             if (list.item(i).getNodeName().equals(tagName))
                 return list.item(i);
         }
         return null;
     }
 }

